Also, I think you should revert your changes to al_create_display_bitmap, and just put you proposed alternative below
(or on a separate page). Right now, it's hard to see the original version anymore, so hard to comment on yours.
Reverted.
maybe you could add some more details what they are good for and why they are needed (and assume someone who only knows the 4.2
drivers, and was not in #allegro - else I will stay the only one who could comment I guess).
Well, the VTABLEs were written on a "provider" basis. The first usable function to create/blit/draw primitives for the given arguments passed, will be used. Let people have a look at the VTABLE of AL_DISPLAY. Open for comments.